After two nights of work, they left with the contents of dozens of safe-deposit boxes, in a methodical heist that has fascinated Britain — and put police on the defensive.

The Daily Mirror newspaper on Saturday published surveillance-camera images that appear to show the thieves in action. The footage shows several men, their faces covered with dust masks, entering and leaving the building repeatedly over the Easter weekend.

London’s Metropolitan Police said detectives had obtained the footage before the newspaper published it, but did not give it to the Daily Mirror.

The force has acknowledged that a burglar alarm at the Hatton Garden Safe Deposit facility was triggered just after midnight on April 3, the start of the holiday weekend, but no one was sent to check on it. The crime was not discovered until businesses reopened on Tuesday.

John O’Connor, former head of Scotland Yard’s armed-robbery squad, told the BBC that the thieves appeared professional and well-prepared, but police had been “utterly incompetent” in not answering the alarm call.

Police say the thieves climbed down an elevator shaft and drilled through concrete walls 2 meters (6 feet) thick into the vault. They stole the contents of 72 safety deposit boxes, which are used by many local dealers to store jewelry.

Police have not disclosed the value of the stolen goods.

Britain has a soft spot for a good heist, and newspapers have reveled in the emerging details of the robbery.

Under the headline “Diamond Geezers,” the Daily Mirror dubbed one red-haired raider in the video footage “Mr. Ginger,” another “Mr. Strong” and a third, who appeared to be wearing expensive shoes, “The Gent.”

Hatton Garden, the center of Britain’s diamond trade, has been hit by several audacious robberies in the past.

In 1987, two armed robbers made off with an estimated 60 million pounds ($90 million at the time) worth of jewels. In 1993, robbers handcuffed shop workers, broke through high-security doors and cracked a safe to steal millions worth of diamonds.